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Hinode and IRIS Observations of the Magnetohydrodynamic Waves Propagating from the Photosphere to the Chromosphere in a Sunspot
Shimizu, Toshifumi; Imada, Shinsuke; Kanoh, Ryuichi
Magnetohydrodynamic (MHD) waves have been considered as energy sources for heating the solar chromosphere and the corona. Although MHD waves have been observed in the solar atmosphere, there are a lack of quantitative estimates on the energy transfer and dissipation in the atmosphere. We performed simultaneous Hinode and Interface Region Imaging S…
Properties of the cluster population of NGC 1566 and their implications
Bastian, N.; Ryon, J. E.; Adamo, A. +2 more
We present results of a photometric study into the cluster population of NGC 1566, a nearby grand design spiral galaxy, sampled out to a Galactocentric radius of ≈5.5 kpc. The shape of the mass-limited age distribution shows negligible variation with radial distance from the centre of the galaxy, and demonstrates three separate sections, with a st…
The Lyman alpha reference sample. VI. Lyman alpha escape from the edge-on disk galaxy Mrk 1486
Verhamme, Anne; Cannon, John M.; Hayes, Matthew +16 more
Context. Recent numerical simulations suggest that the strength of the Lyman alpha (Lyα) line of star-forming disk galaxies strongly depends on the inclination at which they are observed: from edge-on to face-on, we expect to see a change from a strongly attenuated Lyα line to a strong Lyα emission line.
Aims: We aim to understand how a stron…
The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447. I. The X-ray View
Gehrels, N.; Wilms, J.; Kadler, M. +11 more
As part of the TANAMI multiwavelength progam, we discuss new X-ray observations of the γ-ray and radio-loud narrow line Seyfert 1 galaxy (γ-NLS1) PKS 2004-447. The active galaxy is a member of a small sample of radio-loud NLS1s detected in γ-rays by the Fermi Large Area Telescope. It stands out for being the radio-loudest and the only southern-hem…
Searching in the dark: the dark mass content of the Milky Way globular clusters NGC288 and NGC6218
Dalessandro, E.; Mucciarelli, A.; Origlia, L. +8 more
We present an observational estimate of the fraction and distribution of dark mass in the innermost region of the two Galactic globular clusters NGC 6218 (M12) and NGC 288. Such an assessment has been made by comparing the dynamical and luminous mass profiles derived from an accurate analysis of the most extensive spectroscopic and photometric sur…
New Orbits Based on Speckle Interferometry at SOAR
Tokovinin, Andrei
The orbits of 55 visual binary stars are computed using recent speckle interferometry data from the SOAR telescope: 33 first-time orbits and 22 revisions of previous orbit calculations. The orbital periods range from 1.4-370 years, and the quality of the orbits ranges from definitive to preliminary and tentative. Most binaries consist of low-mass …
Distance and extinction determination for APOGEE stars with Bayesian method
Shi, Jianrong; Pan, Kaike; Chen, Bingqiu +3 more
Using a Bayesian technology, we derived distances and extinctions for over 100 000 red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey by taking into account spectroscopic constraints from the APOGEE stellar parameters and photometric constraints from Two Micron All-Sky Survey, as well as a prior …
Pulsating hot O subdwarfs in ω Centauri: mapping a unique instability strip on the extreme horizontal branch
Dhillon, V. S.; Chayer, P.; Fontaine, G. +10 more
We present the results of an extensive survey for rapid pulsators among Extreme Horizontal Branch (EHB) stars in ω Cen. The observations performed consist of nearly 100 h of time-series photometry for several off-centre fields of the cluster, as well as low-resolution spectroscopy for a partially overlapping sample. We obtained photometry for some…
Nine new open clusters within 500 pc from the Sun
Goldman, Bertrand; Röser, Siegfried; Schilbach, Elena
Aims: One of the results of the Milky Way Star Clusters (MWSC) survey was the detection of a slight under-density of old (ca. 1 Gyr) clusters within the nearest kilo-parsec from the Sun. This under-density may be due to an ineffectiveness in the detection of larger structures with lower surface brightness. We report on our attempts to reveal …
X-ray analysis of the galaxy group UGC 03957 beyond R200 with Suzaku
Thölken, Sophia; Reiprich, Thomas H.; Lovisari, Lorenzo +1 more
Context. In the last few years, the outskirts of galaxy clusters have been studied in detail and the analyses have brought up interesting results such as indications of possible gas clumping and the breakdown of hydrostatic, thermal, and ionization equilibrium. These phenomena affect the entropy profiles of clusters, which often show deviations fr…